A few days ago I was cleaning the valve cover (think that's what it's called--top of engine and has the big VOLVO logo on it) using a rag lightly soaked with WD40 to get grime and oily crud off. After that, I used a water-soaked rag to clean away the WD40 so that it won't atttract dust. Of course, I probably wasn't able to completely wipe it all off. Today I was driving and maybe like 2 miles down while at a stop light I started noticing a burning oil smell, the smell that you get when you accidently spill oil on the engine and the heat burns it off. Sniff sniff...is that coming from my car? I pulled into a gas station that happened to be there, opened the hood expecting to maybe see some "smoke" coming off the valve cover. Nothing, but I tried sniffing the engine and only caught a slight whiff of that oil-burning smell from the manifold side. Could that smell have been the residual WD40 burning off? It sorta freaked me out. Normal? No need to be concerned?